To a parent, the medical condition known as Sudden Infant Death Syndrome (SIDS) or apnea is a frightening specter which causes many a sleepless night. As is well known, SIDS is a major cause of death in babies and strikes unexpectedly and often with no warning symptoms. The only effective preventative is a surveillance of the infant. This surveillance has been achieved by parents essentially "standing guard" over their infants throughout the night in one extreme. To a lesser extent, parents have relied on other devices such as walkie talkies left in an open mike condition so that the parent may be reassured by the sound of the infant breathing. While hospitals have developed sophisticated and expensive devices which monitor infants in cribs, the inventor herein is not aware of any device which has been developed and is presently being marketed on a commercial scale of suitable design and cost for home use. While there have been many prior art attempts at such a device, none has been successful in solving this need. The device in the prior art which perhaps comes closest to achieving this is shown in U.S. Pat. No. 4,696,307. The device disclosed in the '307 patent is described as being a self-contained device which is strapped around the torso of a child, the device having an adhesive lining area for adhering it directly to the child's skin and a mechanical displacement transducer which is centrally located within the device such that as the belly of the child deflects upon the child's breathing, the mechanical actuator is actuated. An electronic circuit which monitors the transducer sounds an alarm if it determines that the child is not breathing. The '307 patent states that the adhesive portion of the box is essential for obtaining a significant response by the transducer as the baby's belly moves during breathing. This adhesive attachment provides a reference position and pressure against which the mechanical actuator works to produce a signal indicative of the baby's breathing.
Although the inventor herein has not attempted to test the device disclosed in the '307 patent, it is believed that there are significant disadvantages thereto. For example, proper application of the device to a baby, with the attendant adhesive attachment of the box to the baby's skin, must be quite time-consuming, uncomfortable for the baby, and unreliable in that untrained parents would generally be applying this device to their own baby. Furthermore, this device relies on a baby's belly moving in and out as a baby breathes. However, in some babies it is possible that the deflection of the belly is not as great as in other babies and there is no way to adjust the device for this required difference in sensitivity. While the '307 patent does suggest that ultrasound or hydraulic fluid could be used in place of the mechanical transducer, such would not eliminate the requirement that the device be adhered to the baby's stomach or that there be some pressure exerted on the baby's stomach which could very well be uncomfortable.
Perhaps most importantly, it is not clear to the inventor that the device in the '307 patent would reliably function. It is this concern which has probably interfered with the commercialization of this prior art device as there is certainly a long-felt need for such a device in order to avoid deaths of infants through SIDS.
In order to solve these and other problems in the prior art, the inventor herein has succeeded in designing and developing a breathing monitor which is self-contained, battery operated, includes an electronic circuit with an LED which flashes in response to each breath, an audio alarm in the event there are no breaths detected within a given preselected time period, and a fluid filled bladder coupler which interfaces between the entirety of the device and the baby in order to provide maximum sensitivity with minimal discomfort to the baby and, most importantly, reliable operation. A spring loaded tension adjuster type connector secures an end of an elastic strap to the device enclosure such that it may be snugly fastened about the baby and adjusted to within a proper operating range as indicated by a visual indicator to the parent, thereby affirming to the parent that it has been properly installed. This connector also provides for a limited amount of expansion and contraction, permitted through withdrawal and retraction of the connector from the device enclosure, to accommodate a baby's normal breathing. This further increases the comfort of the device as it is applied to a baby in that the '307 device does not provide for any such expansion or contraction. However, more importantly, this connector permits an inexperienced parent to reliably attach the device to his or her baby and be assured that the device is properly secured and will function properly. This is a major concern as parents must be assured that the device is properly installed in order that they may be relieved and not suffer the anxieties previously felt when no device was available.
As mentioned above, a fluid filled bladder coupler interfaces between the device enclosure and the baby. Unlike the device in the '307 patent, there is no direct contact between the device enclosure and, certainly, no adhesive contact required between the device enclosure and the baby's skin. As such, the present invention may be secured about a baby's night clothes or under garments and yet operate reliably as it responds to a change in tension in the elastic strap which secures the device enclosure to the baby. Furthermore, the invention may be applied to either the baby's back or belly and is not strictly limited to contact with the baby's belly as in the device in the '307 patent. This particular feature can be quite important because there is presently controversy with regard to the proper sleep position for babies in order to minimize the onset of SIDS. Some medical practitioners believe that babies should sleep on their backs which would accommodate application of the invention to a baby's belly while other practitioners believe that babies should sleep on their bellies which would require application of the invention to the baby's back. In either orientation, the present invention will work for the purposes intended.
The inventor has also solved the problem of indicating that the battery is losing its charge and needs to be replaced so that a parent can be assured that battery failure will not attribute to the failure to detect a baby's cessation of breathing in the middle of the night. By cleverly designing the electronic circuit, minimal power drain is achieved such that a single nine volt battery will provide continuous operation for many months. Secondly, the electronic circuit is designed so that an LED flashes as the baby breathes. If the battery is charged sufficiently such that the LED flashes as the baby is placed in its crib for sleep, the battery will have sufficient charge to last at least through that sleep period. Should the LED not flash as the monitor is strapped onto the child, then a parent will know that the battery has discharged dangerously low and needs to be replaced. Although this design provides fail-safe operation, it is anticipated that many parents will routinely replace the battery much more frequently due to the relatively low cost of the battery and their unfailing concern for the safety of their child. Nonetheless, in many cases, it is anticipated that a single nine volt battery will last sufficiently long to see the baby through the riskiest first year of life.
While the principal advantages and features of the present invention have been described above, a more complete and thorough understanding of the invention may be attained by referring to the drawings and description of the preferred embodiment which follow.